SMAD4 and Peutz-Jeghers syndrome: Gene mutations associated with GCYA contributed to hereditary cancer predisposition syndromes: DNA mismatch repair (MMR) genes (MLH1, MSH2, MSH6, and PMS2) and the epithelial cell adhesion molecule (EPCAM) gene in Lynch syndrome, SMAD4 or BMPR1A genes in juvenile polyposis syndrome (JPS), the STK11 tumor suppressor gene in Peutz-Jeghers syndrome (PJS), and the adenomatous polyposis coli (APC) gene in familial adenomatous polyposis (FAP) [31].